95Purple

Topic said it all. I am about to do a 383 for my 95 and been looking at what needs to be done to the block. I have for bolt mais already what is the splayed thing and do you need it? Sounds like something you have done to a cat or dog so it wont breed. :rolleyes:

scorp508

Instead of all bolts going straight into the main caps, you'll have 2 that go in at an angle.

Monty

On a splayed cap block, the outer bolts are splayed outwards 18* or 20*, usually just on the #2, #3, and #4 main caps. Most high-performance aftermarket, and high-end Bow-tie blocks feature this. It is possible to convert a 2-bolt main block over, but it's generally not worth it for a 4-bolt(straight).

The benefit is that by splaying the outer bolts, they engage a much stronger area of the bluck, where the main webs meet with the block.

If you've got a good 4-bolt already, you should be fine unless you're building something for very high rpm and/or hp, higher than is typically built for the street.

vader86

like they said, the bolts just go in at an angle, which makes the bottom end tougher for high hp situations

when i do my 383, im goin with splayed mains

Vette9d1

At what point is the 2 bolt main not enough? Or are you guys just trying to make these engines indestructable? :D

sinistervette

Naturally aspirated, I've yet to find a 2 bolts limitations! I've built many 2 bolts from 302ci. up to 416ci. and have yet to break any of them. I've run several 10.5-1/11.5-1 compression 406's in circle track racing, and had a 355 12.5-1, iron head, solid flat tappet, cast crank,(all because of division rules for stock car) that dyno'd 516hp/485tq. It ran 4 seasons, with new rings and bearings every winter, in a pro stock nova turning 6800-7000 rpm on a 3/8 mile dirt track. Never had a problem. If you think about what the guys like "Grumpy Jenkins" did in the 60's before the 4 bolts, and before large main journal steel cranks, the small block chevy is very tough. It is when you get into forced induction, and spray, that you can really stress test the bottom end! :D :cheers:

Twin_Turbo

Pic says more than words :

95Purple

I understand now. I can see how they would be better then just four straight bolts, where the force could stretch bolt till they yield and break. A side load on the bolts would be harder to break. Thanks for the info.